The invention relates to a manual operating means for the emergency and/or auxiliary operation of a normally electrically or pneumatically actuated valve, comprising a manual operating member which in a ready for use condition is so fixed at a housing recess in the valve in a sealing manner that its inner side faces the interior of the housing recess and its outer side is accessible for the application of a manual operating force.
Such a manual operating means is disclosed in the European patent publication 0 185 168 B1. In the case of this known design a plunger-like manual operating member is held trapped in a housing recess, the housing recess being connected with a receiving space containing a movable valve member. During normal operation of the valve the valve member is electrically and more particularly electromagnetically activated. In an emergency or for test purposes it is however possible for the valve member to be operated manually as well by the application of a manual operating force from the outside on the manual actuating member, which is then shifted and acts on the valve member. In order to ensure that the pressure medium controlled by the valve member does not emerge from the valve member in an uncontrolled fashion, the manual operating member is fixed in the housing""s recess in a sealed manner.
Further designs of manual operating means are for instance disclosed in the German patent publication 4,224,942 A1, in the German patent publication 19,801,201 A1 and the German patent publication 4,203,164 A1.
Independently of the presence of a manual operating means in the case of valves serving for the control of a gaseous medium such as compressed air there is the problem that a certain fraction of the medium to be controlled will spread out in the interior of the valve owing to leakage in a chaotic manner and this leads to gage pressures which in turn may impair the function of the valve.
One object of the invention is to avoid such excess or gage pressure problems and simultaneously to protect the internal components of the valve against damage by foreign matter such as moisture and dirt.
In order to achieve these and/or other objects appearing from the present specification, claims and drawings, in the present invention a manual operating means of the type initially mentioned is characterized in that the manual operating member is provided with venting means which, in order to avoid the establishment of gage pressure in the housing recess due to leakage, render possible the flow of air from the inner side to the outer side thereof and in the opposite direction prevent the entry of non gaseous foreign matter.
It is in this manner that a manual operating means is provided, whose manual operating member simultaneously performs a plurality of functions. On the one hand it serves for the manual or emergency operation of the valve fitted with the manual operating means. On the other hand it performs the function of a cover or closure for closing the associated housing recess in a sealing manner so that foreign matter such as moisture or dirt, not in the form of a gas, is then prevented from entering the valve. Furthermore, it performs a venting function as regards the associated housing and the regions connected with same of the valve and accordingly prevents any undesired establishment of pressure in the interior of the valve due to leakage. All this is achieved with an extremely small number of parts, a small space requirement and at reduced costs.
Although it would be possible to perform the venting of the valve""s interior by separate venting ducts having their own filters which prevent the entry of dirt moisture, the amount of design and manufacturing complexity would then be relatively large, more particularly since the desired manual operating means must be additionally designed as a separate structure.
Advantageous further developments of the invention will appear from the claims.
The manual operating member will best comprise a holding section serving for fixing to the associated valve and an operating section able to be moved in relation to the holding section, a resilient connection being provided between the holding section and the operating section. In this case the holding section is more particularly in the form of a ring and surrounds the centrally placed operating section coaxially, a resilient connecting section extending between the two sections, again in a preferably coaxial manner, such connecting section having a hollow conical configuration and delimiting a funnel-like recess open to the outside. This funnel-like recess or socket is more particularly suitable for the application of a thrusting tool for the manual operating force.
It is preferred for the resilient connection between the holding section and the operating section to have rubber-elastic properties and for same to consist of a material with rubber-like elastic properties, more especially an elastomeric material or rubber. In this connection it is particularly advantageous to employ a manual operating means, whose manual operating member is in the form of an integral body having rubber elastic properties. In any case with the resilient design it is possible to save the costs involved with the additional use of a mechanical return spring and there is the possibility of a particularly low-cost form of manufacture.
The ring-like holding section of the manual operating member can be adapted for fitting in the housing recess of the associated valve with a press fit. Additionally or as an alternative an interlocking attachment in place may be provided for, the holding section being possibly stepped on the outer periphery thereof so that the result is an annular, surrounding holding step or ledge able to cooperate with a ledge inside the housing recess of the associated valve. If the annular holding section is made of a rubber-like resilient, it is then possible to provide for a sealed attachment in place without additional sealing means.
The venting means may be provided in a particularly simple manner if same are in the form of at least one check valve, which permits air flow, due to gage pressure, from the inside to the outside of the manual operating member while nevertheless preventing flow in the opposite direction. Prevention of air flow in the opposite direction simultaneously means the exclusion of foreign matter.
The check valve is preferably designed in the form of a rubber-like resilient material region of the manual operating member, it more particularly being a question of an integral component of the manual operating member. Such a structure is more particularly advantageous when the manual operating member is in the form of an integral elastic member. In order to provide the check valve it is possible for the manual operating member to be slotted in a rubber-like part thereof so that there is an opening which is delimited by sealing faces in closed or sealing contact with each other and which may spread apart to free the opening when there is a gage pressure in the interior of the manual operating member and which after pressure has been equalized may automatically return into engagement with each other with a sealing force operative between them.
In the case of an alternative design the venting means are defined by fine-pored material, as for instance a sintered material, the pore size being so minimized that while it is possible for air to leak off to the outside, liquid and solid foreign matter is prevented from entering. In this manner as well it becomes possible to adhere to the IP 65 safety standard.
Further advantageous developments and convenient forms of the invention will be understood from the following detailed descriptive disclosure of one embodiment thereof in conjunction with the accompanying drawings.